[ENGN2211 Home]

Laboratory Tasks

A variable resistor will be used for the load resistor. It will be adjusted to a range of values, including the value corresponding to full load current.

1.

Measure the max and min values of the variable load resistor.

2.

Assemble the complete power supply circuit, including the transformer.
WARNING: since the circuit is connected to an AC power supply, have the demonstrator check the circuit before you turn it on.

3.

Connect a multimeter set on the 10 A range to measure the load current. Use a CRO or another multimeter to measure the load voltage.

4.

Set the variable load resistor for full load current and measure the load current and voltage. Sketch and measure the ripple voltage.

5.

Set the variable load resistor to its maximum resistance value (to give the lowest value of load current) and measure the load current and voltage. Sketch and measure the ripple voltage.

6.

By adjusting the load resistor, measure the load current and voltage at intermediate values. Tabulate your results, and sketch a graph of load and ripple voltages versus load current (Table 12).

7.

Remove the filter capacitor and observe the waveforms.

Does your design meet the specifications?

What is the effect on the DC load voltage and the ripple voltage as the load current increases?

 

Table 12: Power supply results.

loading	current	voltage	ripple
full load current	500 mA
.
.
.
min load current

 

[ENGN2211 Home]